how accurate is autometer fuelpress gauge ?

[dirtdemon]

... i'm asking because after hooking up the gauge my fuelpress gauge shows ~42psi @ idle (with vac on)

... when i floor it gauge shows around 65 psi :shocked!:

the time i got no gauge for FP, i set it at 47psi at idle and vac off ... with a simply FP-tester

truck is running real nice, but now i'm very upset because i read that the stock fuelrail only holds 60psi ...

... am i about to destroy my fuelrail ???

TIA,pat.

 

[Robert Lone]

Re: how accurate is autometer fuelpress gauge ?

I would try another AutoMeter guage. If they both read the same, trust them...

 

[dirtdemon]

Re: how accurate is autometer fuelpress gauge ?

... what pressure can the stock-fuelrail resist ??

 

[James Thomas]

Re: how accurate is autometer fuelpress gauge ?

... what pressure can the stock-fulrail resist ??

I would say that the gauge is prolly ok. Fuel rails will go over 100 psi. 60+ under boost is common on a lot of builds but fuel delivery starts to drop off under real high pressure. If you can't get what you need by 70 psi or less, you have other issues to look at.

______________
James

 

[wvsaul]

Re: how accurate is autometer fuelpress gauge ?

I run an autometer procomp ultra-light in my supercharged s10 - it has a strange habit of occasionally reading about 20 psi over normal (normal for me at idle is about 45 -so it reads about 65 when acting up). Even when reading high, it still changes with vacuum/boost, so it does not stick exactly, but a couple of taps on the lens when it does this makes it drop instantly to normal and everything is fine again... for awhile.

 

[Matthew Little]

Re: how accurate is autometer fuelpress gauge ?

I have an electric autometer and get 60+ fp. You will get one lbs of fp for one lb of boost increase, so 40 some base fp plus boost and thats your fp number.

 

[dirtdemon]

Re: how accurate is autometer fuelpress gauge ?

I would say that the gauge is prolly ok. Fuel rails will go over 100 psi. 60+ under boost is common on a lot of builds but fuel delivery starts to drop off under real high pressure. If you can't get what you need by 70 psi or less, you have other issues to look at.

______________
James

thx, man - but truck got no bad habits, everythings fine so far ...
... thats why i was upset and was thinking if i have to turn FP down (because of fuelrail) my truck will have to run lean :roll:

... but when you say that it will hold 100psi and 60+ under boost is ok, i'm feeling really fine :tup:

regards, pat.

 

[dirtdemon]

Re: how accurate is autometer fuelpress gauge ?

I run an autometer procomp ultra-light in my supercharged s10 - it has a strange habit of occasionally reading about 20 psi over normal (normal for me at idle is about 45 -so it reads about 65 when acting up). Even when reading high, it still changes with vacuum/boost, so it does not stick exactly, but a couple of taps on the lens when it does this makes it drop instantly to normal and everything is fine again... for awhile.

65 - now thats kinda strange ... mine reads ~ 45psi @ idle and changes like it should ... was confused because of the 60+ @ wot ...

thx for ya help, pat.

 

[dirtdemon]

Re: how accurate is autometer fuelpress gauge ?

I have an electric autometer and get 60+ fp. You will get one lbs of fp for one lb of boost increase, so 40 some base fp plus boost and thats your fp number.

yessir :tup:

pat.

 

[dgoodhue]

Re: how accurate is autometer fuelpress gauge ?

... i'm asking because after hooking up the gauge my fuelpress gauge shows ~42psi @ idle (with vac on)

... when i floor it gauge shows around 65 psi :shocked!:

the time i got no gauge for FP, i set it at 47psi at idle and vac off ... with a simply FP-tester

truck is running real nice, but now i'm very upset because i read that the stock fuelrail only holds 60psi ...

... am i about to destroy my fuelrail ???

TIA,pat.

Stock FP at WOT/boost tops out around 57psi. I have run upper 60's interms of FP, I am sure some other around here are in the mid 70's. I would be more worried about the fuel pump keeping at the higher fuel pressure than the fuel rail leaking.

Every 2in-hg is -1psi of FP. Every 1psi of boost is +1 psi of boost. If you have 42psi of FP at idle and have 20in-hg at idle. Your guage says your running 52psi of base FP and 65psi of FP should be 13 psi of boost.

 

[George Blake]

Re: how accurate is autometer fuelpress gauge ?

You should get 1 psi raise in fuel pressure for every psi of boost. If not, your fpr or fuel pump isn't keeping up. What you need to do is get a cheap, sunpro gauge, put it on the fuel rail, duct tape it to the windshield with the hood off and compare them.

 

[dirtdemon]

Re: how accurate is autometer fuelpress gauge ?

dave, now i'm really confused ...

my fuel pump is from RPM and about 2 months in, so nothing to worry IMO ?!

however - i'm reading 44psi (40 plus to marks ) after fireing it up @ idle and ~65psi @ wot ...

so please correct me if i'm wrong - but what counts for me is :

if i raise my FP further up - will my fuelrail explode ?

i'm asking , because DM shows 850 O2mV's and i 's thinking of enrichen it a lil bit - but w/o destroying my fuelrail ...

TIA,pat.

 

[dirtdemon]

Re: how accurate is autometer fuelpress gauge ?

You should get 1 psi raise in fuel pressure for every psi of boost. If not, your fpr or fuel pump isn't keeping up. What you need to do is get a cheap, sunpro gauge, put it on the fuel rail, duct tape it to the windshield with the hood off and compare them.

thats the point and thats how we did in the past ...

... and i was confused because we set FP @ idle (vac off and plugged) to 47psi - and the gauge reads something different :squint:

 

[dgoodhue]

Re: how accurate is autometer fuelpress gauge ?

What is your Vacuum at idle & how much boost are you running?

 

[dirtdemon]

Re: how accurate is autometer fuelpress gauge ?

20 inHg @ idle
14.7 psi (stock chip & turbo)

so : do i risk my fuelrail when turning FP up ??

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